Power semiconductor switches withstand a blocking voltage of several hundred Volts at high current rating. Typically, a load current through a power semiconductor switch flows in a vertical direction between two principal planes of a semiconductor body. Gate electrodes for controlling the load current may be formed as trench structures extending from one of the principal planes into the semiconductor body. In semiconductor materials with high electric field breakdown strength, shielding regions shield the gate dielectric against a strong electric field in the semiconductor body in a blocking state. The shielding regions may also be function as a body diode, opening a conductive path in the reverse biased state of the power semiconductor switch.
It is desirable to improve the characteristics of semiconductor devices like power semiconductor switches with high blocking capability and reverse conducting body diode.